Rainbow Electronics MAX1644 User Manual
Page 2
MAX1644
2A, Low-Voltage, Step-Down Regulator with
Synchronous Rectification and Internal Switches
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= V
CC
= +3.3V, FBSEL = GND, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
V
CC
, IN to GND ........................................................-0.3V to +6V
IN to V
CC
.............................................................................±0.3V
GND to PGND.....................................................................±0.3V
All Other Pins to GND.................................-0.3V to (V
CC
+ 0.3V)
LX Current (Note 1)...........................................................±3.75A
REF Short Circuit to GND Duration ............................Continuous
ESD Protection .....................................................................±2kV
Continuous Power Dissipation (T
A
= +70°C)
SSOP (derate 16.7mW/°C above +70°C;
part mounted on 1 in.
2
of 1oz. copper) ............................1.2W
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) ............................ +300°C
Note 1: LX has internal clamp diodes to PGND and IN. Applications that forward bias these diodes should take care not to exceed
the IC’s package power dissipation limits.
Hysteresis = 15°C
SHDN = GND
SHDN = GND
I
LOAD
= 0 to
2A,
V
FB
= V
OUT
V
FB
= 1.2V
(Note 2)
V
IN
= V
CC
= 3V, I
LOAD
= 1A, FBSEL = V
CC
I
LX
= 0.5A
FBSEL = REF, V
CC
, or unconnected
V
IN
= V
CC
= 3V to 5.5V,
I
LOAD
= 0, FBSEL = GND or REF
FBSEL = GND
I
REF
= -1µA to +10µA
CONDITIONS
°C
150
T
SHDN
Thermal Shutdown
Threshold
µA
15
I
IN
PMOS Switch Off-Leakage
Current
µA
<1
3
I
CC(SHDN)
Shutdown Supply Current
µA
240
360
I
IN
+ I
CC
No-Load Supply Current
kHz
350
f
Switching Frequency
A
0.25
0.45
0.65
I
IM
Idle Mode Current
Threshold
A
2.5
2.9
3.3
I
LIMIT
Current-Limit Threshold
m
Ω
100
200
R
ON, P
PMOS Switch
On-Resistance
70
150
mV
0.5
1
∆V
REF
Reference Load Regulation
2.500
2.525
2.550
V
3.300
3.333
3.366
V
3.0
5.5
V
IN
, V
CC
Input Voltage
V
1.089
1.100
1.111
V
REF
Reference Voltage
mV
200
V
DO
Dropout Voltage
%
0.4
1.089
1.100
1.111
V
OUT
Preset Output Voltage
Adjustable Output Voltage
Range
V
V
REF
V
IN
0.2
DC Load Regulation Error
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
V
IN
= V
CC
= 4V to 5.5V,
FBSEL = unconnected
V
IN
= V
CC
= 3V to 5.5V,
FBSEL = V
CC
V
IN
= V
CC
= 3V to 5.5V,
FBSEL = REF
V
IN
= 4.5V
V
IN
= 3V
I
LX
= 0.5A
m
Ω
100
200
R
ON, N
NMOS Switch
On-Resistance
70
150
V
IN
= 4.5V
V
IN
= 3V
FBSEL = GND
FBSEL = REF, V
CC
, or unconnected
1
AC Load Regulation Error
%
2
A
2.5
RMS LX Output Current